Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of a disturbed hemostasis as one of the causes of retinal or ciliary vascular occlusions is still controversial. Antithrombin III, protein C and its cofactor protein S were investigated in 25 patients; 14 of them with a retinal vein occlusion, five showed an occlusion of retinal arteries and six of ciliary arteries. Patients with a preceding thromboembolic disease were excluded from the investigations. The mean values (+/- SEM) of antithrombin III (12.1 IU/ml +/- 0.4), protein C (116% +/- 4), total protein S (102% +/- 3) and free protein S (46% +/- 2) were equivalent to the mean values of a normal population. Neither does a defect or a lack of coagulation inhibitors have an essential influence on the development of an isolated retinal or ciliary vascular occlusion nor does the local occlusive vascular disorder influence the activity of systemic inhibitors.
 ...
PMID:[Inhibitors of blood coagulation in vascular occlusion of the retina and optic nerve]. 214 89

Activated protein C (APC) is an antithrombotic enzyme. The therapeutic potential of infused human recombinant APC (rAPC) was studied in a primate model of platelet-dependent thrombosis. Eight baboons with chronic femoral arteriovenous shunts received rAPC infusions for 1 hour. The shunts were extended with 5-cm long, 4-mm-i.d. thrombogenic Dacron graft segments for the time of infusion. The plasma level of the enzyme, the blood flow in the shunt, and the deposition of indium-111-labeled platelets and iodine-125 fibrinogen on the graft were measured. The influence of rAPC infused at doses of 0.25 and 1.0 mg/kg-hr was compared with the effects of control infusions of saline. Five of eight control grafts occluded within 60 minutes, whereas there was no change in the blood flow during rAPC infusion. Deposition of platelets was inhibited by 13 +/- 10% and by 42 +/- 13% (mean +/- SEM) after 30 minutes of infusion at the two doses, which gave rise to circulating rAPC plasma concentrations of 0.4 and 1.9 mg/l, respectively. Both doses significantly inhibited fibrin deposition in the graft. Circulating plasma markers of thrombus formation and of fibrinolysis did not increase significantly during rAPC infusion; measurements of bleeding time were also within normal limits. Thus, rAPC, like human plasma-derived APC, inhibited thrombus formation without impairing primary hemostasis.
 ...
PMID:Inhibition of thrombus formation by activated recombinant protein C in a primate model of arterial thrombosis. 237 13

Activated protein C is a potent, physiologic anticoagulant that inactivates the activated forms of factors V and VIII as well as facilitates in vivo fibrinolysis. We developed a competitive protein-binding enzyme-linked immunoadsorbent assay (ELISA) for protein C that was utilized to investigate if the hypercoagulability of the nephrotic syndrome is related to a deficiency of circulating plasma protein C. Protein C was measured in plasma of 11 patients with nephrotic syndrome (24 hr protein 8.4 +/- 1.6 g, SEM; serum creatinine 4.2 +/- .74 mg/dl, SEM). Ten azotemic nonnephrotic patients were employed as controls (serum creatinine 6.0 +/- 1.25 mg/dl, SEM). No significant reduction of protein C values was observed (mean 108%, range 65-200%) in nephrotic patients when compared with the controls (mean 127%, range 100-200%) even though protein C antigen was present in all nephrotic urine samples tested. Also, no correlation existed between blood levels of urea nitrogen, creatinine, albumin, total protein, or 24-hr urine protein excretion and the observed protein C values. These results suggest that in patients with the nephrotic syndrome, a hypercoagulable state may not be related to a deficiency of protein C and that the level of this zymogen in nephrotic syndrome reflects a dynamic balance between urinary losses and systemic production.
 ...
PMID:Protein C levels in nephrotic syndrome: use of a new enzyme-linked immunoadsorbent assay for protein C antigen. 308 87

The components of the factor VIII complex were estimated by immuno- and bioassays in 85 patients with liver disease. The plasma concentrations of the antigens were elevated in 65% (VIII:CAg) and in 76% (VIIIR:Ag) of patients while the biological activities were elevated in only 14% (VIII:C) and 15% (VIII:RiCof). There was no correlation with C-reactive protein, used as a measure of an acute phase reaction (X2 = 0.7; P = 0.1); or with severity of liver disease as judged by prothrombin ratio (P = 1.0) but highest values were observed in patients with cholestatic liver disease. Following parenteral vitamin K there was a significant fall in both the biological activity of VIIIC (36%) and of VIII:CAg (38%) in 13 vitamin K deficient patients (P less than 0.001) but no change in 23 vitamin K replete patients or in the VIIIR:Ag levels in either group. Factor V levels were lower in patients with parenchymal liver disease (0.54 +/- 0.1 units/ml, mean +/- SEM, n = 12; normal range 0.5-1.5 units/ml) than in patients with extrahepatic cholestasis who were vitamin K deficient (1.2 +/- 0.1 units/ml, P less than 0.0001). The levels of protein C antigen, the vitamin K dependent protease which inactivates factors VIII:C and V, was at the lower end of the range in both groups (0.7 +/- 0.1, mean +/- SEM, n = 18, normal range 0.74-1.4 units/ml). There was no significant change in either protein C antigen or factor V following vitamin K. The discrepancy between the biological activity of factor VIII and the antigen levels could represent accumulation of partially degraded factor VIII or production of a hypoactive form. There is no evidence that the reduction in VIIIC and VIII:CAg following vitamin K was mediated by protein C.
 ...
PMID:The effect of liver disease on factors V, VIII and protein C. 393 41

While plasma fibrinogen level and clotting factor VIII activity obviously increased during the acute inflammatory reaction caused by intramuscular injections of turpentine in 10 rabbits, the activity of plasma protein C, with anticoagulant and antithrombotic effects, was found to display a slight yet significant (p < 0.02) decrease. When compared to protein C activity in humans, this vitamin K-dependent serine protease was found to be lower in rabbits (52, 7% +/- 3,63 of standard human plasma) and this activity decreased to 45,8% +/- 2,80 (mean +/- SEM), 48 hours after the injection of turpentine. This slight decrease should however be interpreted in the context of other disturbances of the hemostatic balance caused by inflammation and may contribute to the intravascular deposition of fibrin.
 ...
PMID:Hemostatic balance during the acute inflammatory reaction. (II). With special reference to plasma protein C. 889 73

Serious thrombotic complications occur in sick neonates, while healthy infants have a very low risk of thrombosis. To better understand the regulation of physiological anticoagulation at birth, components of the protein C pathway were measured in cord plasma samples from 14 full-term healthy newborns and in samples from 10 adult controls. Although zymogen protein C was significantly reduced in cord plasma (mean +/- SEM in cord vs. adult sample 37 +/- 1.4% vs. 90 +/- 5.5%, p < 0.0001), levels of the active enzyme, activated protein C (APC), were not (119 +/- 20% vs. 75 +/- 12%, p = 0.0762). Relative to the protein C level, cord plasmas had a 5.2-fold higher APC level (p < 0.01). The APC increase was partially due to slower inactivation of APC in cord plasma (half-life for APC 50 min in cord plasma vs. 27 minutes in adult plasma). Increased sensitivity of factor V to inactivation by APC in cord plasma was observed since the activated partial thromboplastin time-based APC sensitivity ratio was significantly increased for cord vs. adult plasma samples (2.28 +/- 0.09 versus 1.97 +/- 0.03, p < 0.01). Thus, despite low zymogen protein C, the protein C pathway in newborns seems to be functionally well developed and at an activated stage at birth.
 ...
PMID:Upregulation of the antithrombotic protein C pathway at birth. 984 42

To assess possible interactions between inflammation and activation of the anticoagulant protein C system during post-ischemic reperfusion protein C, APC, neutrophil L-selectin expression and myocardial myeloperoxidase activity (MPO) were measured in 19 patients undergoing cardiopulmonary bypass. After reperfusion for 10 min, APC to protein C ratio (APC/PC) increased from pre-reperfusion value 1.43 +/- 0.12 (mean +/- SEM) to 2.25 +/- 0.29, p = 0.015. Negative correlations were observed between APC/PC and MPO activity (Spearman r -0.64, p = 0.007) and APC/PC and neutrophil L-selectin expression (r = -0.7, p = 0.007, demonstrating that post-ishemic protein C activation was associated with decreased neutrophil tissue sequestration. Thus, physiological protein C activation may be involved in regulation of the inflammatory injury during reperfusion of human ischemic coronary circulation.
 ...
PMID:Activated protein C and inflammation in human myocardium after heart surgery. 1139 22